Workers use block and tackle method to lay concrete blocks for construction of a water tunnel in United States.

Block and tackle arrangement used to lay concrete blocks for the construction of a water tunnel in United States. Concrete blocks on a car. Workers use block and tackle to remove pre-cast concrete lining block from a car on rails and attach it to the erector arm of block and tackle system. The erector arm swings around towards the ceiling of the tunnel and lowers the block on the ground. Several blocks are removed in this manner.